There are numerous gas scrubbers in existence, including for example scrubbers that operate upon flue gasses of power plants. When liquid absorbents are used, the liquid is sprayed into the gas stream either in a counter-current or a cross-current configuration. Problems arise because the gas tends to flow in a laminar fashion around the fluid droplets, which reduces effectiveness of the scrubbing.
Basic principles of scrubbing are set forth in Schiffner, Kenneth C., et al., “Wet Scrubbers”, 2nd Ed, Technomic Publishing Co., Inc., pp 1-10; Buonicore, Anthony J., et al., “Air Pollution Engineering Manual”, Air and Waste Management Ass'n, pp 78-88; Cooper, David C. et al., “Air Pollution Control”, 3rd Ed, Waveland Press, pp 115-118, 209-238.
One solution is to direct the sprays against a target barrier through which the gas is flowing. Exemplary targeted barriers include plastic balls, and metal or ceramic saddle rings. Disruptions of the spray and gas streams caused by the barrier facilitate interaction of the spray and gas, but considerable energy is expended to force the gas through the barrier at sufficient velocity to provide adequate scrubbing.
Patent publication WO 84/03641 to Jones describes an improved rotary scrubber that uses a rotating mechanical atomizer. The rotating atomizer disperses high velocity water droplets in a radial direction that is cross-current to the gas stream flow. However, the water droplets can rob the gas of forward momentum reducing the ability for interaction with downstream targets.
Thus, there is still a need for apparatus and methods that facilitate scrubbing of gasses and liquid absorbents in a scrubber.